Collecting mud at low tide

The sea level in the Bay of Bengal fluctuates several metres every day, when the tide is low the wall workers fill sand sacks for the base of a new wall. Sea level globally has risen by approximately 17 centimetres in the past century with an average increase of 3,4 millimetres per year since satellite measurements began in 1993. Pre industrial era rise is estimated at just 0,2 millimetre per year.